Z-score to Probability Calculator
Instructions:
- Enter a Z-score to find the corresponding area under the curve (AUC)
- The result shows the probability P(Z ≤ z) - area to the left of Z
- Z-scores can be positive or negative
Example: 1.96, -1.645, etc.
Probability Results
Area under the curve (left tail):
-
Probability Visualizations
Probability to Z-score Calculator
Instructions:
- Enter a probability (percentile) to find the corresponding Z-score
- The probability should be between 0 and 1
- This calculates the Z-score that gives the specified left-tail probability
Example: 0.975 for 97.5th percentile
Z-score value:
-
Common Values Reference
| Percentile | Z-score | Common Use |
|---|---|---|
| 0.9000 (90%) | 1.2816 | 80% confidence interval |
| 0.9500 (95%) | 1.6449 | 90% confidence interval |
| 0.9750 (97.5%) | 1.9600 | 95% confidence interval |
| 0.9900 (99%) | 2.3263 | 98% confidence interval |
| 0.9950 (99.5%) | 2.5758 | 99% confidence interval |